Compositional fingerprints of chromian spinel from the refractory chrome ores of Metalleion, Othris (Greece): Implications for metallogeny and deformation of chromitites within a "hot" oceanic fault zone

Kapsiotis A., Rassios A. E., UYSAL İ., Grieco G., Akmaz R. M., Saka S., ...Daha Fazla

JOURNAL OF GEOCHEMICAL EXPLORATION, cilt.185, ss.14-32, 2018 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 185
  • Basım Tarihi: 2018
  • Doi Numarası: 10.1016/j.gexplo.2017.11.003
  • Dergi Adı: JOURNAL OF GEOCHEMICAL EXPLORATION
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.14-32
  • Anahtar Kelimeler: Laser-ablation ICP-MS, Chromian spinel (Cr-spinel), Chromitite, Ophiolite, Othris, Greece, MELT-ROCK INTERACTION, MID-ATLANTIC RIDGE, UPPER-MANTLE, PODIFORM CHROMITITES, OMAN OPHIOLITE, SUBDUCTION INITIATION, PALEOTRANSFORM FAULT, VOLCANIC-ROCKS, TRACE-ELEMENTS, SILICATE MELT
  • Karadeniz Teknik Üniversitesi Adresli: Evet

Özet

The chrome ores of the retired Metalleion mine of the Othris ophiolite are hosted in a small volume of a pervasively serpentinized, tabular harzburgite body. These ores have been studied to determine their geological mode of occurrence, mineralogy and chromian spinel (Cr-spinel) chemistry. The ores consist of massive chromitite (85-95% modal Cr-spinel) with mylonitic fabric in imbricate-shaped pods. Chromian spinel displays a limited range in Cr# [Cr/(Cr + Al) x 100 = 53-63] and Mg# [Mg/(Mg + Fe2+) x 100 = 59-73] and low TiO2 content (<= 0.11 wt%). Minor- (Ti, Ni, V, Mn and Zn) and trace-element (Sc, Co and Ga) concentrations do not show any significant variations from Cr-spinel cores to boundaries and were not considerably modified by post-magmatic processes. However, Cr-spinel compositions show slight enrichments in Zn and V, and depletions in Ti and Sc when compared to the composition of chromite from the East Pacific Rise mid-ocean ridge (MOR) basalts. The composition of Cr-spinel from the Metalleion chromitites is quite anomalous on a global perspective as these ores are not clearly associated to a suprasubduction zone (SSZ) or MOR chemistry.